LCD monitor flickering when Printer is switched on

user28

Journeyman
I have an 22 inch BenQ LCD monitor, Model VW2245 and a Ricoh SP210 SU -USB Laser printer (900 watts). I have been observing a strange behaviour with my monitor. Whenever I switch on the printer the screen flickers on the monitor or the display switches off and on. The distance between the printer and LCD monitor is 10 inches approximately and both are placed on a wooden table.

The power connection is as follows.
From a single 6 Amps AC wall socket protected by a 10 Amps MCB, my 700 VA APC UPS is connected.
The UPS has 2 battery backup sockets and 2 Surge protection sockets(no battery backup for these surge protection sockets)

I connected the CPU power, monitor, speakers and my router to a power strip and the power strip is connected to one of the battery backup sockets in the UPS.
The printer is connected directly to the non battery backup surge protection socket in the UPS.

Apart from these nothing are connected to the UPS.


For this flickering problem, initially I suspected that the mains MCB might not be bearing the load of the printer and got it upgraded to 10 Amps (initially had a 6 Amps MCB). I got the mains AC wall socket also double checked for any loose contacts but everything seems to be fine from an electrical view point.

I heard about the electrical noise interference that causes to the monitors but not sure if that would also apply to LCD monitors. Is this the cause? If yes does it damage the monitor?

The flickering only happens once when the printer is switched on and does not repeat again until the printer is switched off and on again.

Clueless as if this is the due to the interference caused by the printer or the electrical voltage load or the UPS is the problem.

Can anybody guide me please.
 

icebags

Technomancer
does monitor go off-on when you switch on other things in household ?

try connecting printer to some other wall plug point, away from pc. and check.
 
OP
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user28

Journeyman
No the problem does not happen to the monitor when other things in the household are operated. not happening if he printer is connected to other wall plug. Is the single wall socket unable to bear the load when the printer is powered on or is the UPS which is faulty?
 

icebags

Technomancer
No the problem does not happen to the monitor when other things in the household are operated. not happening if he printer is connected to other wall plug. Is the single wall socket unable to bear the load when the printer is powered on or is the UPS which is faulty?

yah just keep it away. it may be load issue, or may be RF issue. possibility is your plug/extension cords may not be of very good quality thick wires, whereas 900W is a big load, really fetches lots of current. so, voltage may trip.

just make sure you are not using any thin, not good quality wires anywhere and just keep it away, connected to some other plug.
 

topgear

Super Moderator
Staff member
This is your problem :

I connected the CPU power, monitor, speakers and my router to a power strip and the power strip is connected to one of the battery backup sockets in the UPS.
The printer is connected directly to the non battery backup surge protection socket in the UPS.

You should not connect printer with a 700VA ups which also serves power to your whole pc.
 
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